The design solution to the Charles River School's new Activity Center included the conversion and expansion of the existing tennis barn into a multi-functional, modern gymnasium for both basketball and tennis programs, and a multi-purpose dining facility.

The lower level of the two-story addition includes physical education faculty offices, athletic equipment storage, along with a sizable lobby and adjacent hallway used for class dismissal and pre-assembly space for the Gymnasium. A large communal dining room and kitchen, located on the second floor are utlized for school lunches and a variety of academic programs and faculty functions.

The fenestration of the front façade, a similar design element throughout the campus, provides ample natural light and picturesque views of the common from both levels.